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HelpTest Code LAB3532 Unfractionated Heparin Activity
Clinical System Name
Unfractionated Heparin Activity
Synonyms
LAB3532
anti-Xa activity
HEP UNF
Heparin Activity Unfractionated
Heparin Unfractionated
UFH
Sample Requirements
Specimen: Whole Blood
Container(s): Lt. Blue/Citrate
Required Vol: one 1.8 mL tube or one 2.7 mL tube (do NOT over or under fill)
Minimum Vol: N
Note: This is enough for a PT, PTT, HEP UNF, and Fibrinogen on the same sample. Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volume. Use of a Vascular Access Device for the collection of coag testing is not recommended.
If a venipuncture is not possible and drawing from a line is necessary:
a. Draw from a heparin-free line.
b. If patient has a line infused or flushed with heparin, such as an arterial line or central venous line, waste the following volume:
A 6-mL waste volume for PIVs, PICCs, temporary venous lines (femoral, jugular) and Baby Broviacs.
A 12-mL waste volume for all other permanent lines (Hickman, Portacath, HD, tunneled lines).
Blood must be transferred to the Lt. Blue/Citrate tube by use of a blood transfer device to ensure proper fill.
Processing Instructions
Main Campus CPA: Core Technologist will process specimen. Deliver blood directly to Core Coag bench.
Reject due to: Clotted, Hemolyzed, Insufficient quantity (underfill), or Improper collection (overfill).
Spin: Y
Aliquot: Y
Storage location: Core 14 Freezer ( -70 C).
Core Technologist: Specimen should be centrifuged within 1 hour of collection. Spin whole blood, remove plasma. Transfer upper 3/4 layer of plasma to plastic tube affixed with large computer label.
Off-site collection: Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volume, note the fill line on the tube. Use of a Vascular Access Device for the collection of coag testing is not recommended. If this method is used it requires a 5 mL waste volume; 3 mL for size 2 French catheter or smaller. Blood must be transferred to the Lt Blue/Citrate tube by use of the blood transfer device.
Specimen should be centrifuged within 1 hour of collection. Double spin, transfer upper 3/4 layer of plasma to plastic tube affixed with large computer label. Freeze until solid one aliquot of 1.0 mL plasma in plastic tube at -70C (preferred) or -20C.
Non-Children's Hospital Off-site collection: Ship completely frozen on dry ice.
Children's Regional Clinics: Ship completely frozen in frozen Nalgene Labtop cooler with ice pack inside an insulated soft cooler.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Citrated platelet-poor plasma | Room temp | ≤4 h |
| Refrigerated | N | |
| Frozen -20 C or -70 C | ≤3 m |
Availability
| STAT | Performed | TAT |
|---|---|---|
| Y |
Daily |
1 h |
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Coagulation
Phone Number: 206 987-2617 (Client Services)
CPT Codes
85520
Methodology
Method: Chromogenic Substrate by STA-R MAX
Analytical Volume: 1 mL plasma
This is enough for a PT, PTT, HEP UNF, and Fibrinogen on the same sample.
Limitations: This assay requires antithrombin III (ATIII) in patient's plasma. Low level of ATIII may underestimate the heparin level.
Results affected by moderate lipemia, moderate hemolysis, and moderate icterus.
High hematocrit greater than or equal to 56% requires a citrate adjusted tube.
Description
Unfractionated heparin (UFH) is used for the prevention and treatment of thromboembolic diseases. The quantitative determination of plasma unfractionated heparin levels is useful for monitoring treatment efficacy.
Therapeutic Range
The therapeutic range for Unfractionated Heparin Activity is 0.3 - 0.6 Anti-Xa IU/mL.
Heparin activity is reported in Anti-Xa IU/mL (Anti-Xa International Units/mL).
Critical Values
Greater than or equal to 1.10 International Units/mL